1. Field of the Invention
The present invention relates to an integrated microelectromechanical system (MEMS) method of trapping and collecting a biological sample, processing the sample, and analyzing the result to detect and identify the sample. The invention is useful for the detection of biological warfare agents, hazardous bacteria in agricultural products and prepared food, genetic-based biomedical assays, and mapping DNA of the human genome.
2. Description of Related Art
Dielectrophoresis (DEP)has been used very successfully by researchers at the University of Texas MD Anderson Cancer Center to separate various types of cells, such as cancerous from non-cancerous cells [F. F. Becker, X.-B. Wang, Y. Huang, R. Pethig, J. Vykoukal, and P. R. C. Gascoyne, xe2x80x9cThe Removal of Human Leukemia Cells from Blood Using Interdigitated Microelectrodes,xe2x80x9d J. Phys. D: Appl. Phys. 27 (1994) 2659]. In addition, they have demonstrated the use of DEP to concentrate DNA in specified regions. In other work, a Japanese group has demonstrated manipulation of DNA in solution [Morishima et al., xe2x80x9cMicroflow System and Transportation of DNA Molecule by Dielectrophoretic Force Utilizing the Conformal Transition if the Higher Structure of DNA Moleculexe2x80x9d, IEEE 0-7803-3744-1, 1997].
Such DEP separation process as involve applying an alternating electric field through a series of interdigitated electrodes. By choosing an appropriate excitation frequency, specific cells or particles (DNA in our case) become trapped in the high field gradient regions at the electrode tips. Other particles can then be flushed out of the system, leaving the attracted particles of interest behind for subsequent collection. The University of Texas group has demonstrated this procedure for the removal of human leukemia cells(x) from blood (o) as in FIG. 2 [F. F. Becker, X.-B. Wang, Y. Huang, R. Pethig, J. Vykoukal, and P. R. C. Gascoyne, xe2x80x9cThe Removal of Human Leukemia Cells from Blood Using Interdigitated Microelectrodes,xe2x80x9d J. Phys. D: Appl. Phys. 27 (1994) 2659].
It is an object of this invention to detect and identify biological agents.
It is a further object of this invention to assist in mapping the human genome and other genetic-based biomedical assays by allowing a fully automated microsystem based on microelectromechanical systems (MEMS).
It is still another object of this invention to detect hazardous bacteria in agricultural products and prepared food.